Home Built 13" Jointer #5: Motor Mount

With a 50lb motor, I needed a way to mount it securely, and also have a way to adjust the belt tension.

I came up with the motor mounted to a block, that would key into another securely mounted block. Two carriage bolts hold the motor in place, and the keyed slot keeps the motor parallel to the ground.

I started by gluing up two blocks of baltic birch, to get 1-1/2” thick. I did a lot of measuring to make sure the pulleys would line up, as my CAD model was off a little (5/16”). Using a forstner bit, I drilled the counterbores for the four carriage bolts to mount the motor. Then followed those with 5/16” through holes.I then drilled the holes for the bolts that would hold the motor in place, and used the CNC to route the slots that would provide the belt adjustment.

Once that was done, I used a dado set in the table saw to cut the slot for the sliding key, and then cut some dadoes on the backside for mounting brackets. Then glued and screwed the 4 mounting brackets into the dadoes.

Calculating the belt length was a bit of an issue. I used a calculator I found, and ordered a belt. It ended up being about 18” too long. So next, I did the math, and ordered another one. This one was what I was expecting. I didn’t do the CAD work until I had the belt and pulleys, so I could actually measure the center to center distance.

I didn’t want to glue the mounting bracket in until I was sure it would be in the right place, so I used some double faced tape to hold it in place, and added two screws to support the weight of the motor.I then put the motor in, and put on the belt. Success! The mount was almost perfectly centered in the adjustment slot, so I can get it loose enough to put the belt on, and then still tension it properly. The motor itself also has slotted holes, so I have an additional ±1/2” if I ever need it.

I Ran out of time tonight to glue the mount in, but I did get it all back apart. The motor mount will now be glued to the front panel, with about 10 screws to keep it from going anywhere.

I still need a few little items before I can wire up the motor and test it. I bought a 10ft cord, but I think I’m going to get a longer one, as I’ll need about 3-4ft of the cord to reach the motor and switch. I’ll probably end up with a 15ft cord, which should work well in my current shop, as I have a 220 outlet on each wall. My plan right now is to get the motor running on Saturday. Then I’ll start working on the tables.